Experimental Evaluation of Suspension Stability

Aggregation means coarsening of the size distribution. The rate of size changes can, therefore, be considered as a measure of the microscopic stability. In principle, one can use any particle sizing technique for the purpose of stability characterisation— provided that the sample preparation does not affect aggregation and that both preparation and measurement time are well below the characteristic time scale(s) of the aggregation process. For dilute suspensions, one usually employs optical sizing techniques. 

In contrast to dilute suspensions, it is rather difficult to further dilute dense suspensions without affecting the interfacial properties, the particle interaction, and the qualitative aggregation behaviour. Even more, dilution of dense suspensions 

2 Stability from Monitoring Scattering and Extinction of Radiation 

For very tine, non-aggregated colloidal particles, the light scattering obeys Rayleigh s scattering law  

Note that the transition from the Rayleigh scattering of the primary particles to the fractal RDG scattering of the aggregates is not only reflected in the absolute value of scattering intensity, but also in its wavelength dependency. 

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